A schematic diagram for MSI hardware (board MS-16H2, MS-16H21). Shared as “MS-16H2 MS-16H21-VER 11 PDF.rar” — a .rar file, 2.27 MB.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @alischematics. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.